ML19351A044
| ML19351A044 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 03/31/1981 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | AFFILIATION NOT ASSIGNED |
| Shared Package | |
| ML19351A040 | List: |
| References | |
| NUDOCS 8106250095 | |
| Download: ML19351A044 (1) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION s
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REGION V
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1990 N. CALIFORNIA BOULEVARD Qd SUITE 202, WALNUT CREE K PLAZA o
4,,,5 WALNUT CREEK. CALIFORNIA 94596 March 31,1981 1
Gentlemen:
The enclosed circular is forwarded for your information.
No written response to this circular is required.
If you have any questions related to this matter, please contact this office.
Sincerely, hm (0~
e R. H. Engelken Director
Enclosure:
IE Circular No. 81-05 8106250 h
SSINS No: 6830 Accession No.:
80110f.s282 IEC 81-05 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 31, 1981 IE Circular No. 81-05: SELF-ALIGNING R0D END BUSHINGS FOR PIPE SUPPORTS
Background:
By letter dated July 24, 1980, Bechtel Power Corporation notified NRC of gencric deficiencies in pipe support sway struts furnished by Corner &
Lada, Inc., to the Callaway and Wolf Creek sites. The specific deficiencies identified involved the clamp end of the sway strut becoming loose and possibly being disengaged from the bushine. This could result in a large gap in the support system not accounted for in the original analysis. This deficiency was reported to NRC pursuant to 10 CFR Part 21 on May 14, 1980.
In another letter dated October 8,1980, Bechtel Power Corporation notified NRC of generic deficiencies in pipe support end bushings at Midland Units 1 and 2 and at Palisades.
In this report, self-aligning rod end bushings on the ends of sway struts and snubbers furnished by ITT Grinnell, Pacific Scientific, NPSI, and Corner & Lada were foun6 to be partially or totally disengaged from the structural component. This report was identified as a 10 CFR Part 21 notification.
Discussion:
The problem of loose bushings in snubber and sway strut assemblies is potent-ially generic to all sizes of all manufacturers' as_enbles. However, the potential for complete disengagement of the bushing from the assembly is limited to those cases in which the assembly is attached to a clamp where the gap is sufficiently large to permit the paddle to slide completely over the bushing.
The consequences of complete disengagement of the bushing would be to inval-idate the original analytical assumptions used in the piping analysis, potent-ially creating an overstress condition in the piping er overloading the supports. This would be more significant for the seismic event since the
--canewchanmdhudvnanir charactorjr.+ics of the system and lead to impact g N vy:ymgy;;g gn 2'
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DUPLICATE ~ DOCUMENT have been to replace the defectiva place. However, some of the staked n3 Entire document previousl",
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shing is possible. This method would h
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